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Intro
CVE-2026-48864 is a heap buffer overflow vulnerability discovered in libsolv, a library used for solving package dependencies. The flaw resides in the `repopagestore` component when decompressing attacker-controlled compressed data within `.solv` files. Due to insufficient input validation, specially crafted `.solv` files can trigger an out‑of‑bounds memory write.
The attack vector is local: an attacker must provide a malicious `.solv` file and induce a victim application (e.g., dumpsolv, dnf, zypper, or any binary that calls repo_add_solv) to process it. The overflow occurs because the decompressor does not verify the size of the incoming compressed data against the allocated heap buffer. When the decompressed output exceeds the expected bounds, the library writes past the end of the buffer.
This can lead to three primary outcomes:
- Information disclosure (reading adjacent heap memory)
- Code execution (overwriting function pointers or structured exception handlers)
- Denial of service (crashing the application)
The vulnerability is triggered during the processing of a `.solv` file, which is a binary format for repository metadata. Applications like `dumpsolv` read these files to display their contents. By embedding a specially crafted compressed page inside a `.solv` file, the decompressor’s bounds check is bypassed, leading to a heap overflow.
Red Hat rates this as Moderate severity with a CVSS 3.1 base score of 7.8 (HIGH). The score reflects the low attack complexity, no privileges required, and the need for user interaction (the victim must open the file). The confidentiality, integrity, and availability impacts are all rated High.
The issue was discovered by AISLE in partnership with Red Hat and made public on May 26, 2026. As of the publication date, no official patch is available, but upstream fixes are expected.
DailyCVE Form:
Platform: libsolv
Version: Affected
Vulnerability : Heap Overflow
Severity: Moderate
date: 2026-05-26
Prediction: 2026-06-26
What Undercode Say
Analytics
Check if your system uses libsolv ldd /usr/bin/dumpsolv | grep libsolv.so Find libsolv version rpm -q libsolv RHEL/Fedora dpkg -l libsolv Debian/Ubuntu Simulate crash with a malicious .solv file dd if=/dev/zero bs=8192 count=1 of=poc.solv (Actual exploit requires a crafted header – PoC not public)
Exploit
- Craft the `.solv` file: Set the compressed page header fields to values that cause the decompressor to miscalculate the required buffer size.
- Deliver the file: Social‑engineer the victim into opening the file with any tool linked against `libsolv` (e.g.,
dumpsolv poc.solv). - Trigger the overflow: The library calls
solv_calloc(maxsize + DATA_READ_CHUNK + 4, 1). If `maxsize` is negative, the allocated buffer is too small, yet `fread()` later writes `DATA_READ_CHUNK` (8192) bytes into it.
Protection
- Do not open untrusted `.solv` files until a patch is applied.
- Use a wrapper that validates the `.solv` header before passing it to
libsolv. - Apply the vendor patch as soon as it becomes available (expected in June 2026).
- Run vulnerable applications inside a restricted container or with system call filtering.
Impact
- Confidentiality: Heap memory can be leaked, potentially exposing sensitive data (e.g., cryptographic keys, user data).
- Integrity: An attacker may overwrite critical heap structures, leading to arbitrary code execution.
- Availability: Crashing the application or the entire dependency resolution process (e.g., `dnf update` hangs or crashes).
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Sources:
Reported By: github.com
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